Knowledge of the topics and analysis of investment projects is an important prerequisite for further achievement of the set goals with the selected project. The very definition of investment and division gives an idea of what makes it up, the way of determining the discount rate and what are the prerequisites for the definition and application of the discount rate. Two very important terms for projects and their implementation are described as risk and uncertainty that provide important parameters for defining the discount rate. The discount rate for companies is defined in different ways. This is stated for those companies that have their shares on the stock exchange and that are used with several different sources of WACC funding as the most 2 commonly applied discount rate. Of course for every project and company the best application is not always WACC because cannot determine the measure of my risk due to non-participation in stock exchange trading. Therefore, there are other types of discount rates. Only the determination of capital projects and their cash flows provides one of the essential prerequisites for successful project evaluation. Applying the discount rate to the evaluation of investment projects is an action that is preceded by a lot of work and consideration of many factors. The methods used for investment evaluation are given in addition to their previously set rules, decisions on the acceptability or rejection of the project.